Familiality of neural preparation and response control in childhood attention deficit-hyperactivity disorder.

BACKGROUND: Patients with attention deficit-hyperactivity disorder (ADHD) exhibit difficulties in multiple attentional functions. Although high heritability rates suggest a strong genetic impact, aetiological pathways from genes and environmental factors to the ADHD phenotype are not well understood. Tracking the time course of deviant task processing using event-related electrophysiological brain activity should characterize the impact of familiality on the sequence of cognitive functions from preparation to response control in ADHD. Method Preparation and response control were assessed using behavioural and electrophysiological parameters of two versions of a cued continuous performance test with varying attentional load in boys with ADHD combined type (n = 97), their non-affected siblings (n = 27) and control children without a family history of ADHD (n = 43). RESULTS: Children with ADHD and non-affected siblings showed more variable performance and made more omission errors than controls. The preparatory Cue-P3 and contingent negative variation (CNV) following cues were reduced in both ADHD children and their non-affected siblings compared with controls. The NoGo-P3 was diminished in ADHD compared with controls whilst non-affected siblings were located intermediate but did not differ from both other groups. No clear familiality effects were found for the Go-P3. Better task performance was further associated with higher CNV and P3 amplitudes. CONCLUSIONS: Impairments in performance and electrophysiological parameters reflecting preparatory processes and to some extend also for inhibitory response control, especially under high attentional load, appeared to be familially driven in ADHD and may thus constitute functionally relevant endophenotypes for the disorder.

A technique for the fast sampling of biological tissues for electron paramagnetic resonance spectroscopy.

A simple technique for the fast sampling of biological tissues for electron paramagnetic resonance (EPR) spectroscopy is described. By using tube-like stainless steel cutter, a cylindrical piece of tissue is dissected free; while holding the sample and cutter on a silicone rubber cutting base, the sample is transferred directly into the EPR test tube by pushing the tube into the instrument. The main features of the technique are its simplicity, speed, elimination of the necessity to manipulate frozen tissue (e.g., breaking, chopping, etc.), precise information on the sample volume, the ability to adjust sample size according to need, and avoidance of the use any foreign compounds (such as spin traps). The technique has been successfully applied to the EPR detection of free radicals in rabbit spinal cord exposed to ischemia. It can be easily modified for manipulation with samples in an inert atmosphere.

An approximate approach to DNA denaturation.

A quantum-statistical-mechanical theory of equilibrium states was developed to present a simple realistic model of DNA denaturation. Applying the Feynman free energy minimum principle approach to the free energy of an anharmonic oscillator representing an interchain H-bond between DNA strands a simple formula for its melting temperature was derived. Experimental Raman and IR vibrational data were used, and if not available the vibrational data for individual H-bonds in guanine-cytosine and adenine-thymine base pairs were assigned using the Prohofsky self-consistent phonon approach; moreover, the Morse potential parameters were taken over from the same source. On the basis of them the H-bond force constants and then H-bond melting temperatures were calculated for individual H-bonds in the base pairs. The calculated average melting temperatures were compared with the experimental ones for various samples of DNA. Very reasonable results were obtained.

The steady state stability criterion of a simple model of calcium channels.

A simple known model of calcium inactivation is described and qualitatively analysed. Stability conditions at the level of a stationary state with respect to some small perturbations in the concentration of Ca2+ ions are analysed from the point of view of the Prigogine non-equilibrium thermodynamics. Possible internal fluctuations in Ca2+ ion concentration are discussed as connected with fluctuations of the potential energy of interaction between calcium ions and the binding sites.

[Disorders of hepatic circulation and imaging with color doppler ultrasonography]. / Poruchy hepatálnej cirkulácie a moznosti ich zobrazenia farebnou dopplerovskou ultrasonografiou.

The authors analyse disturbances of hepatic circulation and the possibilities of their imaging by colour Doppler ultrasonography (CDU) in combination with standard B two-dimensional imaging. The predominance of arterial perfusion in liver cirrhosis, portal vein thrombosis, malign diseases of the liver, or extraluminal obstruction of portal vein are changes which can be imaged by means of high-quality colour Doppler imaging. CDU is a non-invasive method of evaluation of portal hypertension, namely of prehepatic, hepatic and posthepatic type. It is a method of investigation of the viability of the hepatic artery after transplantation of the liver, including that of surgical portocaval anastomoses and transjugular intrahepatic portosystemic shunts. (Fig. 6, Ref. 33.).

[Prophylactic effects of ceftriaxone in patients after endoscopic papillosphincterotomy]. / Preventívny úcinok ceftriaxonu u pacientov po endoskopickej papilosfinkterotómii (EPS).

In thirty patients after EPS and gall extraction for cultivation ceftriaxon in preventive dose 1 g was administered. This group of patients was compared with a group of 30 patients after EPS without preventive administration of antibiotic from clinical and biochemical point of view. Most frequently occurring bacteria in the gall of patients after EPS were Pseudomonas aeruginosa and E. coli. All of the detected bacteria were sufficiently sensitive to ceftriaxon. Preventive effect of ceftriaxon was manifested in statistically significant fall of hyperbilirubinemia and hyperamylasemia 24 hours after EPS (p > 0.05). (Tab. 5, Ref. 8.)

[Colonoscopy monitoring intervals after polypectomy of adenomas of the large intestine in patients younger than 40 years of age]. / Intervaly kolonoskopických kontrol po polypektómii adenómov hrubého creva u pacientov mladsích ako 40 rokov.

A group of patients younger than 40 years of age, who had been subdued to endoscopic large intestine adenoma polypectomy were compared with the rest of the patients regarding the adenoma occurrence according to sex, localisation, histologic character, frequency of recurrence, and carcinoma formation in the large intestine in the site of previous polypectomy. The compared groups of patients differed merely in time of recurrence. In patients over 40 years of age the adenomas reoccurred most frequently in the first and fifth years following the primary polypectomy. In patients after primary polypectomy regular colonoscopic controls were suggested, namely after the first year and subsequently after every two years. This scheme is appropriate also for patients under the age of 40 years. Therefore the recommended intervals of colonoscopic controls at this age category do not require to be subdued to alteration. (Tab. 14, Ref. 5.)

[Triple combination antimicrobial therapy of Helicobacter pylori and basal levels of serum gastrin]. / Trojkombinacná antimikróbna liecba Helicobacter pylori a bazálna hladina sérového gastrínu.

BACKGROUND: The etiopathogenic relationship of Helicobacter pylori (HP) infection to chronic active antrumgastritis and peptic ulcer disease has been confirmed by a number of studies. The key role in the development of peptic lesions belongs to hypergastrinemia. This is supposed to be related to ammonium synthesis in the antral area influenced (promoted by HP and resulting in interruption) weakening of the negative feedback mechanism maintaining intraluminal acidity. OBJECTIVES: In our present study we focus our attention to the effectiveness of triple antimicrobial therapy in HP positive patients with chronic active antrumgastritis residing in the lowering of the level of serum gastrin. METHODS: There was a group of 15 patients in our current study with HP positivity as well as chronic active antrumgastritis documented by endoscopy, histology, microbiology and serology respectively. Endoscopical and histological findings were classified according to "The Sydney System". The whole group was evaluated on an ambulatory basis, those with active ulcer, endocrinopathy and biliary tract disorders were excluded. The basal level of serum gastrin was evaluated by RIA-test-gastrin before and after successful antimicrobial therapy. RESULTS: In our group of 15 patients with HP infection in coexistence with chronic active antrumgastritis we have found a significant decrease in the basal level of serum gastrin (p = 0,01) after successful therapy. CONCLUSION: The decrease in the basal level of serum gastrin after eradication of HP confirms the importance of HP infection in the pathogenesis of peptic lesions in stomach and duodenum. We consider the antimicrobial therapy in chronic active antrumgastritis in HP positive patients to be a fully indicated therapeutic approach. (Tab. 1, Fig. 1, Ref. 10.).

Free radicals in rabbit spinal cord ischemia: electron spin resonance spectroscopy and correlation with SOD activity.

1. In nonanesthetized rabbits temporal occlusion of the abdominal aorta was used to induce oxidative stress in the lower part of the body including distal segments of the spinal cord. 2. Spinal cord samples were taken from the animals exposed to 25-min aortic occlusion (AO) or to occlusion followed by 1- or 2-hr reperfusion (AO/R1 or AO/R2, respectively) or from sham-operated animals (C). The presence of free radicals (FR) in the spinal cord samples frozen in liquid N2 was assessed by ESR spectroscopy without spin trapping. Moreover, superoxide dismutase (SOD) activity and conjugated diene (CD) levels were measured in the samples. 3. In the AO group FR were detected in the spinal cord regions close to the occlusion (lower thoracic and distal segments) along with a decrease in SOD activity. The calculated g value (g = 2.0291) indicated that the paramagnetic signal recorded might be attributed to superoxide radicals. FR were absent in the AO/R1 group. Concurrently, the SOD activity revealed a significant tendency to return to the control level. FR appeared again in the AO/R2 group, mostly in the upper and middle lumbar regions, along with a decrease in SOD activity. No sample from the C group revealed FR. A significant increase in CD levels was observed in the thoracolumbar region only in the AO/R2 group. The temporary absence of FR in the AO/R1 group suggests activation of defense antioxidant mechanisms (e.g., specific enzymatic systems such as SOD), which might have been exhausted later. 4. Changes in SOD activity similar to those observed in the thoracolumbar region, though less noticeable, occurred in the obviously noncompromised tissue (upper cervical region). This points to a kind of generalized response of the animal to aortic occlusion. 5. Direct ESR spectroscopy revealed the presence of FR as well as their time course in the spinal cord during the early phase of ischemia/reperfusion injury and the inverse relationship between FR and SOD activity.

1H NMR ganglioside ceramide resonance region on the differential diagnosis of low and high malignancy of brain gliomas.

1. The high-resolution 1H NMR (MRS) spectra of human brain tumor homogenates revealed a broad resonance at 5.3-5.4 ppm in glioblastoma multiforme (N = 16) and brain metastases (N = 3). The broad resonance was identified as ceramide, a sphingosine-fatty acid combination portion of ganglioside, indicating an elevated abundance of monounsaturated fatty acids. GLC analysis of gangliosides in the highly malignant glioblastoma multiforme revealed that the elevated monounsaturated fatty acid is oleic acid (C18:1). The resonance at 5.3-5.4 ppm region was not detectable in normal human brain (N = 2), in meningiomas (N = 2), or in low-grade astrocytomas (N = 12). In normal human brain the abundance of monounsaturated fatty acid is minimal. 2. This investigation was made possible because the method of producing homogenate resulted in (i) no loss of lipids during the process and (ii) a well-homogenised sample, with (iii) no loss in chemical integrity. 3. The properties of tumor gangliosides include antigenic specificity and immunosuppressive activity and the ceramide, a sphingosine-fatty acid combination, noticeably influences the ganglioside immunosuppressive activity. 4. The observation of 1H NMR ceramide resonance in high-malignant brain tumors emphasizes the dramatic role of aberant gangliosides and ceramide precursors on the grade of malignancy and invasiveness. 5. Further insight into the specific nature of the ceramide portion of gangliosides in grading the malignancy of brain tumors should be investigated further.